<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script>
        let obj={
            a:1,
            b:2
        }
        // for (let value of obj) {
        //     console.log(value);
            
        // }
        console.log(Object.keys(obj));
        
    </script>
</head>
<style>
    .box{
        width: 200px;
        /* height: 100px; */
        background: lightblue;
    }
    .a{
        width: 100px;
        height: 100px;
        background-color: lightcoral;
        float: left;
    }
</style>
<body>
    
    <div class="box">
        <div>555s555</div>
        <div class="a"></div>
        <!-- <span>11111</span> -->
        <!-- <span>222222222222222222</span> -->
    </div>
</body>
</html>